Participants of the experiment LHCb at the Large Hadron Collider (LHC) at CERN, including the Novosibirsk State University and the Institute of Nuclear Physics SB RAS, announced the observation of the four «exotic» states in the decay of B-mesons on J-psi meson (J / ψ ), phi meson (φ) and kaons (K-mesons). The states are interesting, because of the fact that there are neither mesons nor baryons.
Participants of the experiment have found four new states in the decays of B-mesons on J-psi meson (J / ψ), phi meson (φ) and kaons (K-mesons), three of them - X (4274), X (4500) and the X (4700) - have been discovered for the first time (a numeric index - an indicator of energy megaelectronvolts). All of them decay at J-psi meson and phi meson.
J / ψ-meson consists of a charmed quark and an antiquark, φ-meson - of a strange quark and an antiquark; kaon contains a strange quark (antiquark) and one u- or d-quark (antiquark)
An indication of the status of the registered particle X (4140) for the first time has been obtained in the CDF experiment (Fermilab) and later confirmed in CMS (LHC) and D0 (Tevatron), but was not detected electron-positron detectors BaBar in the USA and Belle in Japan.
States are interesting, because of the fact, that they do not contain the upper (u) and lower (d) quarks that compose the nucleons (protons and neutrons).
- The states are called exotic because they are not ordinary mesons (quark-antiquark) or baryon composed of three quarks, - said a senior researcher at the Laboratory of Physics of heavy quarks in hadron interactions of NSU, Pavel Krokovny.
Possible hypotheses for these particles: 4-quark states (Enchanted (c) and the strange (s) quarks and antiquarks) or a bound state of two strange, charmed mesons Ds ± Ds *.
According to Paul Krokovnogo words, this type of monitoring can be passed only by studying the mass of states J / ψ and φ. Physicists used a complex multidimensional amplitude analysis, which helped not only find a new state but also to determine their quantum numbers. Each of the
four particles observed at a value of more than five standard deviations. In other words, the probability that it is a statistical fluctuation - less than one in a million.